The wise person is the key to understand many spiritual concepts, is the person gifted by the spiritual love, also called "Agape" or love of Charity.
And what is "Agape"? Agape is the Greek name to designate the form of love that arises when the desire of the good prevails, is the love perfected by the nature of the good, is the love without passions.
The wise is the man who loves the good, is the person pure of heart, is the happy heart man.
The philosophers called him in different ways: for Aristotle the wise, for Plato the philosopher, for Rousseau the legislator, for the christians the man pure of heart or the providential man.
But why correspond to the wise to lead?, Why does spiritual leadership correspond to the wise? 
Because is typical of the wise the proper domain. The proper domain is a perfection of the character, a fruit of the spirit. The proper domain is an ership associated to the love of the good, the love of God, also known as Agape; because the low passions are extinct, like envy, jealousy, hate, anger, resentment. Remember that the wise is the man pure of heart, that is the reason of the extinctions of the low passions.
The spiritual power is the power perfected by the proper domain. The proper domain has internal direction, the power external. Domain or proper domain and power are complementary concepts.
The leaders who have no proper domain are slaves of their own passions and passenger desires. Only the person who controls oneself, and that' s mean proper domain, is truly free and do the things right because is right.
The wise is the person gifted by the spiritual power and that' s why corresponds to the wise to lead and not to be led.
One reason is clear from all the authors: without him, societies cannot develop their dreams and the idea of common good.